Spectrometers> Applications > Photonics West 2008 Abstracts
We are delighted to support some of our collaborators at the Photonics West 2008. Please visit their presentations or visit P&P Optica’s booth #6098 in the Canadian Pavilion to find out more about their exciting research!
Speckle reduction algorithm for optical coherence tomography based on Interval Type II Fuzzy Set
1Dept. of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
2Dept. of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
Phone : +1 519 888 4567 x 35665; Fax: +1 519 746 8115; E-mail: ppuvanat@engmail.uwaterloo.ca
Abstract:
A novel speckle reduction technique based on soft thresholding of wavelet coefficients using interval type II fuzzy system was developed for reducing speckle noise in Optical Coherence Tomography images. The proposed algorithm is an extension of a recently published method for filtering additive noise by use of type I fuzzy system. Unlike type I, interval type II fuzzy based thresholding filter considers the uncertainty in the calculated threshold and the wavelet coefficient is adjusted based on this uncertainty. Application of this novel algorithm to optical coherence tomography images of a finger tip show reduction in speckle with little edge blurring.
Dispersion cancelled low coherence interferometry
1Dept. of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
2Dept. of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
3Institute of Quantum Computing, University of Waterloo, Waterloo, Ontario, Canada
4Clarendon Laboratory, University of Oxford, Parks Rd, Oxford, United Kingdom
5ICFO – Institut de Ciencies Fotoniques, Mediterranean Technology Park,Castelldefels (Barcelona), Spain
Abstract:
Even-order dispersion cancellation, an effect previously identified with frequency-entangled photons, is demonstrated experimentally for the first time with a linear, classical interferometer. A combination of a broad bandwidth laser and a high resolution spectrometer was used to measure the intensity correlations between anti-correlated optical frequencies. Only 14% broadening of the correlation signal is observed when significant material dispersion, enough to broaden the regular interferogram by 4250%, is introduced into one arm of the interferometer.
High speed (47,000 lines /s), high resolution Fourier Domain Optical Coherence Tomography system at 1060nm
1Dept. of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
2Dept. of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
3Sensors Unlimited, Goodrich, NJ, USA
Abstract:
An ultrafast, high resolution optical coherence tomography system operating in the 1060nm wavelength region is presented for the first time. It utilizes a prototype infrared CCD camera with a 1024 pixel linear array and 47,000 lines /s readout rate, and a custom built non-scanning spectrometer. When interfaced to a superluminescent diode (Superlum, lc = 1020 nm, Dl = 108 nm and Pout = 9 mW) 4.3µm x 6.5µm (axial x lateral) is achieved in biological tissue. At 17µs integration time and 1.3mW incident power the maximum system’s sensitivity is 104 dB. In-vivo images of human finger tip are acquired as a preliminary test of the system’s performance.
Enhancement of third harmonic contrast with harmonophores in multimodal non-linear microscopy of histological sections
1Department of Chemical and Physical Sciences, and Institute for Optical Sciences, University of Toronto
2Sunnybrook Health Sciences Centre and Department of Medical Biophysics, University of Toronto
Abstract:
Histological investigations of biological tissue benefited tremendously from staining different cellular structures with various organic dyes. With the introduction of new imaging modalities such as second harmonic generation (SHG) and third harmonic generation (THG) microscopy, the demand for novel dyes that enhance the harmonic signals has arisen. The new labels with high molecular hyperpolarizability have recently been termed harmonophores. In this study we demonstrate that hematoxylin, the standard histological stain used in H&E (hematoxylin and eosin) staining, enhances the microscopic THG signal. Hematoxylin has an affinity for basophilic structures such as the cell nucleus, ribosomes and mitochondria, while eosin stains structures such as the cytoplasm, collagen and red blood cells. The histological sections of H&E stained cancerous prostate tissue found in transgenic adenocarcinoma of the mouse prostate (TRAMP) have been investigated with the multimodal SHG, THG and multiphoton excitation fluorescence (MPF) microscope. Strong THG signal revealed intracellular structures originating where the hematoxylin stain resides, while SHG imaging of the tissue showed the presence of collagen fibrils in the extracellular matrix. The MPF was mostly present in the extracellular matrix. The spectrally and temporally resolved MPF revealed that most of the fluorescence originates from the eosin. The THG image did not correlate with MPF confirming that the harmonic signal originates from hematoxylin. Multimodal nonlinear microscopy adds invaluable information about cellular structures to the widely used bright field investigations of H&E stained histological sections, and can be efficiently used for morphological investigations as well as cancer diagnostics.
